Drying apparatus for wood-pulp and other matters



1. D. ULLGREN. DRYING APPARATUS FOR WOOD PULP AND OTHER MATTERS. APPLICATION FILED SEPT. 25, 1918.

`v1,37 6,659. Patented May 3, 1921.

Affari/vn. o!

PATENT OFFICE.

JOHAN DANIEL ULLGREN, OF STOCKSUND, SWEDEN.

DRYING APPARATUS FOR W'OOD-PULP ANI) OTHER MATTERS.

Application filed September 25, 1918.

To all whom it may concern Be it known that I, JOHAN DANIEL ULL- GREN, a subject of the King of Sweden, and resident of Villa Dalstugan, Stocksund, in the Kingdom of Sweden, have invented certain new and useful Improvements in Drying Apparatus for Wood-Pulp and other Matters, of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to drying apparatus for wood pulp and other matters of that class, in whichthe matter is moved through a channel or the like, in which it is subjected to the action of heated air or any other gaseous medium. According to the invention the said channel is divided preferably into two sections, the heated air being forced into the channel at its ends and exhausted at the point of connection of the sections. The circulation of theair through the sections is effected preferably by means of fans and, owing to the fact that the fan of each section forces into the channel the Same quantity of air as is exhausted by the same, no air can pass from outside intovthe channel, for which reason the ends of the channel may be fully open (without doors, shutters or the like), which considerably simplifies the construction of the drying apparatus and the running of the same. Owinef to the fact that the air is introduced into the drying channel at its ends, as already stated, the air of that section, at which the matter is introduced into the channel, moves in the same direction as the matter, so that the air comes into contact with the matter, as the air is hottest, as distinguished from drying apparatus operating according to the counter-current system. The said temperature of the air may be considerably higher than the temperature which the matter bears in dry condition, so that the difference between the temperatures of the air and the matter may be very considerable, which results in a greater effect of the heated air being obtained than is the case in drying apparatus hitherto used.

In the accompanying drawing Figure 1 is a longitudinal section ofa drying apparatus arranged in accordance with this invention. Fig. 2 is a horizontal section on the line 2-2 of Fig. 1. Figs. 3 and 4 are sections on the lines 3 3 and 4-4 respectively of Fig. 2, and Fig. 5 shows a modified form of theapparatus. The drying appa- Specifcaton of Letters Patent.

Patented May 3, 1921.

Serial No. 255,669.

ratus is shown'only diagrammatically in the drawing.

1 is the drying channel, through which the matter to be dried is moved, for instance by means of cars, endless chains or the like. The matter is introduced into the channel 1 at its left end. 2 and 3 are two chambers, which, according to the drawing, are located above the channel 1, but may be provided below the same as shown in Fig. 5. In the said chambers 2 and 3, which are separated from one another by a wall 4, fans 5 and 6 respectively are located. The fan 5 forces the air into the channel 1 through a heating device 7, consisting in the drawing of a plurality of pipes, through which passes the steam from a steam generator (not shown). The heating device may, however, be of any other suitable type, Vsince its precise construction forms no part of the actual invention. From the chamber 2 the heated air passes into the channel 1 through an opening, which is located at its left end and preferably is provided with deflectors 8 having an oblique direction downward and inward toward the channel and turning the air current into the channel. At the partition wall`4 an opening 9 is provided, which connects the channel 1 with the chamber 2 the channel into the chamber by the fan. The air is then saturated with moisture absorbed from the matter. For the precipitating of the said moisture the air passes through a condenser, which may be of any suitable type. In the drawing it consists of a plurality of parallel pipes 10. The air passes through the spaces between the pipes 1() and cold air is forced through the pipes from the chamber 3 in the manner stated below. The air, freed from the moisture, is then forced by the fan 5 through the heating device 7, the channel 1 and so on. The path of the air is indicated by arrows. The fan 6 of the chamber 3 forces the air from the chamber through an opening, which is provided with oblique deiiectors 11 of the same construction as the defiectors 8 and located at the right end of the channel 1, at which the matter is discharged. The air forced into the channel 1 by the fan 6 is again sucked by the said fan into the chamber 3 through an opening 12 located at the partition wall 4 and through a condenser 13 for separating from the air the moisture absorbed by the same while passing through and through which the'air is sucked from denser 13 communicates with the channel 18. The said channel 18 communicates at its left end, separated from the chamber 2, through the pipes 10 with the left end of the channel 19, which is also separated from' the chamber 2. The right end of the channel 19 communicates with the fan 6. Owing to the said arrangement the air freed from moisture by the condenser passes through the channel 18, pipes 10 and channel,19 to the fan 6. Owing to the fact that the moist air, leaving the left section of the channel 1 and passing between the pipes 10 is comparatively warm and the air passing from the chamber 17 is comparatively cold, the device comprising the pipes 10 serves partly as a condenser for the left section of the channel 1 and partly as an airheater for the right section of the said channel, so that no special heater is necessary for the section last mentioned. A smaller heater 20 (Fig. 5), of the same construction as the heater 7 or of any other construction may, however, be provided in thevchamber 3, behind the fan in order to increase the temperature of the circulating air, if not sufiiciently heated when passing the condenser 10.

As seen from the above, the hot air, leaving the chamber 2 meets the moist matter, to be dried, as it enters the channel 1. Consequently, the difference of the temperatures of the air and the matter here is greatest during the whole drying operation, in consequence whereof an eiicacious drying takes place. The air moves inthe same direction as the matter and absorbs more and more moisture from the same. In theV other, cooler section of the channel 1 on. the other hand the counter-current system is applied, so that the drying air, which is hottest as it enters the channell, removes the last residues of moisture from the matter. The same quantity of air is forced into the sections respectively of the channel 1 as is sucked from the samev where the sections communicate. The drying air, freed from moisture and re-heated, is again Vused in the channel 1. Owing to the described arrangements the ends of the channel 'may be fully open. In some cases, for instance in the drying of wood, the matter is introduced 'into thechannel 1 at its cooler end`(the right end) in order `to be subjected to a slight heating at first and then to the action of a highertemperature, as the matter enters the left section.

The invention may evidently be modied in many respects without exceeding the limits of the same.

Having now described my invention, what I claim as new and desire to secure by Let ters PatentY is:

1. In a drying apparatus for wood pulp and other material the combination of a channel through which-the matter is moved, said channel being provided at its ends with inlet openings for drying air, and being also provided at intermediate points with outlet openings for the said air, oblique deflectors provided in the said inlet openings, and means for exhausting the drying air through the said outlet openings and then forcing the same into the channel through the said inlet openings, substantially as described and for the purpose set forth.

2. In a drying apparatus for wood pulp and other material the combination of a channel, through which the material is moved, Y

said channel being provided at its ends with inlet openings for drying air, and being also provided at intermediate points with outlet openings for the said air, chambers, which are provided for the sections respectively of ends with inlet openings for drying air, and

being also provided at intermediate points with outlet openings for the said air, means for forcing the air through the sections respectively of the channel located between the inlet and outlet openings, .a heating device for the air passing through one of the said sections, a device for cooling the air leaving the said section and removing the moisture of the same, a condenser provided for the other section, and means for leading the air from the said condenser through the said cooling device, so that the cooled air serves as cooling medium in the said device and simultaneously is heated, substantially as described and for the purpose set forth.

In witness whereof, I have hereunto signed my name.

JOHAN DANIEL ULLGREN. 

